Information Handling System Radio Antenna Selection and Control

ABSTRACT

A portable information handling system rotationally couples main and lid housing portions to each other with a hinge having opposing faces. One of a first or second antenna set disposed on the opposing faces is selected to support wireless communication by a radio disposed in the housing based upon the rotational orientation of the hinge. Optimal antenna selection is confirmed by comparing return signal strength indicator or bit rate error of the first and second antenna sets.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates in general to the field of informationhandling system wireless communication, and more particularly to aninformation handling system radio antenna selection and control.

Description of the Related Art

As the value and use of information continues to increase, individualsand businesses seek additional ways to process and store information.One option available to users is information handling systems. Aninformation handling system generally processes, compiles, stores,and/or communicates information or data for business, personal, or otherpurposes thereby allowing users to take advantage of the value of theinformation. Because technology and information handling needs andrequirements vary between different users or applications, informationhandling systems may also vary regarding what information is handled,how the information is handled, how much information is processed,stored, or communicated, and how quickly and efficiently the informationmay be processed, stored, or communicated. The variations in informationhandling systems allow for information handling systems to be general orconfigured for a specific user or specific use such as financialtransaction processing, airline reservations, enterprise data storage,or global communications. In addition, information handling systems mayinclude a variety of hardware and software components that may beconfigured to process, store, and communicate information and mayinclude one or more computer systems, data storage systems, andnetworking systems.

Portable information handling systems continue to shrink in size andincrease in capability. End users appreciate small portable systems thatreadily travel so that end users can access information on-the-go.Generally, end users who have to perform input intensive tasks whilemobile will rely on portable information handling systems that integratea keyboard, such as systems that have a convertible or clamshellconfiguration. For example, convertible and clamshell systems have amain housing portion that contains processing components and a lidhousing portion that contains a display. End users can make inputs tothe information handling system through a touch screen of the display orthrough an integrated mechanical keyboard that is typically located onan upper surface of the main housing portion. The main and lid housingportions rotationally couple to each other with a hinge that supportsthe display in a viewing position relative to the integrated keyboard.In convertible systems, the housing portions rotate 360 degrees relativeto each other so that the display is exposed for use as a tablet.Various types of convertible portable information handling systemsassemble processing components, an integrated keyboard and display in avariety of other arrangements. For example, some tablet informationhandling system couple and decouple to a main housing portion for use asa tablet separate from the main housing portion. Such system includeprocessing components in the lid portion and communicate through a wiredor wireless interface with a main housing portion that integrates thekeyboard and supporting processing components.

Generally, a portable information handling system length and width isdetermined by the size of the display integrated in the housing. Endusers generally pick a portable information handling system based on adesired display size, however, end users expect to have as muchperformance as possible packed into a housing that is as light weightand thin as possible. Decreasing information handling system housingheight and improving ergonomics associated with typed inputs at aminimalist housing presents a number of difficulties. For example, toinclude adequate processing power, thermal constraints drive processorplacement and housing form factor. Often, ergonomic constraints and thedesire for robust housing mechanics lead to housing designs that havenarrow top and side borders with added strength focused near the hingeassembly that rotationally couples the main and lid housing portions toeach other. Other processing components are generally placed in thehousing portions as space allows with some compromises accepted toperformance where required.

One consideration for portable information handling systems is that endusers rely heavily upon wireless communication to interact with networksand peripheral devices. Indeed, portable information handling systemoften have limited numbers of ports for transferring data a power sothat wireless communication is the primary interface for performing mostinformation handling system operations. One difficulty with the use ofwireless communications is that the efficiency of antennae integrated inthe information handling system tends to vary considerably based uponthe placement of the antennae and the operating configuration of housingportions. Conventional antenna placement is generally in the lid portionopposite the hinges so that wireless signals have a clear path out ofthe information handling system. However, thin height housings restrictspace available for antenna placement. Suboptimal antenna placement canlead to a poor user experience with performance varying dramaticallybased upon the system's configuration.

SUMMARY OF THE INVENTION

Therefore, a need has arisen for a system and method which provides aninformation handling system low profile housing that provides wirelessantenna performance under varying operating configurations.

In accordance with the present invention, a system and method areprovided which substantially reduce the disadvantages and problemsassociated with previous methods and systems for wireless antennaplacement and operation with rotationally coupled portable informationhandling system housing portions. First and second antenna disposed onopposing sides of a hinge selectively support wireless communicationbased at least in part on the hinge orientation.

More specifically, a portable information handling system is built withmain and lid housing portions rotationally coupled to each other by ahinge, such as with processing components disposed in the main housingportion and a display disposed in the lid housing portion. A radiodisposed in the housing supports wireless communication between theprocessing components and external devices, such as through wirelesswide area, local area and personal area networks. The hinge couples tothe main and lid housing portions to have opposing faces that shift inorientation relative to the housing portions as the housing portionsrotate relative to each other. A first antenna set of plural antennaecouple to a first face of the hinge and a second antenna set of pluralantennae couple to a second face of the hinge opposite the first face.As the housing portions rotate relative to each other, the opposingfaces move between a first housing orientation having the first antennaset in a preferred position for wireless communication on the firsthinge face to a second housing orientation having the second antenna setin a preferred position for wireless communication on the second hingeface. The radio selects one of the first or second antenna sets toperform wireless communication based upon the housing orientation.Further analysis may then be performed to confirm that an optimalantenna set is selected, such as by comparing the return signal strengthindicator (RSSI) or bit rate error (BRE) associated with wirelesscommunication by one or more the antenna of each antenna set. Furtherimprovements in antenna efficiency are achieved by altering theoperation of unselected antenna, such as by detuning the unselectedantenna or interfacing an unselected antenna to ground,

The present invention provides a. number of important technicaladvantages. One example of an important technical advantage is thatantennae placed proximate a hinge assembly provide improved wirelessperformance in varying operational configurations. Locating antennaeproximate the hinge provides enhanced robustness for mounting andreduces wiring and cables associated with placing antenna distal theradio, such as coaxial cables that would run through the minimal spaceprovided under a thin touchscreen display. Reduced cable length providesimprove radio frequency signal loss and less difficulty balancingimpedance across cable paths that may vary in housings of differentdimensions. Opposing antennae located at the outer surface of a hingeassembly allows selection of an antenna for use that has the bestefficiency based sensed factors, like housing position and RSSI, whilealso using the inactive antenna as a ground for directing RF energy.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may he better understood, and its numerousobjects, features and advantages made apparent to those skilled in theart by referencing the accompanying drawings. The use of the samereference number throughout the several figures designates a like orsimilar element.

FIG. 1 depicts a blown-up view of a portable information handling systemhaving first and second antenna disposed on opposing faces of a hingethat rotationally couples main and lid housing portions relative to eachother;

FIG. 2 depicts a side perspective cutaway view of first and secondantennae oriented relative to each other with main and lid housingportions in a closed position;

FIG. 3 depicts a side perspective cutaway view of first and secondantennae oriented relative to each other with main and lid housingportions in a tablet position;

FIGS. 4A and 4B depict radiation patterns extending from a portableinformation handling system having restricted and optimized antennaconfigurations;

FIG. 5 depicts a side cutaway view of first and second antenna coupledto opposing faces of a hinge;

FIG. 6 depicts a flow diagram of a process for selecting an antennabased upon housing orientation; and

FIG. 7 depicts a flow diagram of a process for selecting an antennareturn signal strength and/or bit rate error.

DETAILED DESCRIPTION

Antenna sets disposed in a hinge of a portable information handlingsystem are selected to support wireless communication based at least inpart upon housing orientation that alters the relative hinge positions.For purposes of this disclosure, an information handling system mayinclude any instrumentality or aggregate of instrumentalities operableto compute, classify, process, transmit, receive, retrieve, originate,switch, store, display, manifest, detect, record, reproduce, handle, orutilize any form of information, intelligence, or data for business,scientific, control, or other purposes. For example, an informationhandling system may be a personal computer, a network storage device, orany other suitable device and may vary in size, shape, performance,functionality, and price. The information handling system may includerandom access memory (RAM), one or more processing resources such as acentral processing unit (CPU) or hardware or software control logic,ROM, and/or other types of nonvolatile memory. Additional components ofthe information handling system may include one or more disk drives, oneor more network ports for communicating with external devices as well asvarious input and output (I/O) devices, such as a keyboard, a mouse, anda video display. The information handling system may also include one ormore buses operable to transmit communications between the varioushardware components.

Referring now to FIG. 1, a blown-up view depicts a portable informationhandling system 10 having first and second antenna 40 disposed onopposing faces of a hinge 38 that rotationally couples main and lidhousing portions relative to each other. In the example embodiment,portable information handling system 10 has a main housing portion 12and a lid housing portion 14 rotationally coupled to each other by ahinge assembly 36 so that lid housing portion 14 holds an integrateddisplay 16 in an elevated position for end user viewing. Main housingportion 14 holds processing components that cooperate to processinformation. In the example embodiment, a motherboard 18 interfaces acentral processing unit (CPU) 20 and random access memory (RAM) 22 toexecute instructions for processing information. For example, theinstructions are provided from one or more applications stored inpersistent memory, such as a solid state drive (SSD) 24. A chipsetincludes controllers and flash memory to executed firmware thatcoordinates operation of the processing components, such as a BasicInput/Output System (BIOS). An embedded controller 28 provides aninterface between human interface devices and CPU 20, such as keyboard,mouse and touchscreen input devices. A wireless network interface card(WNIC) 30 supports wireless communication, such as through a wirelesslocal area network (WLAN), a wireless wide area network (WWAN) and/or awireless personal area network (WPAN). Motherboard 18 is integrated inmain housing portion 12 and covered by a main housing upper surface 32having an integrated keyboard 34. In alternative embodiments,alternative types of configurations may be used, such as by integratedprocessing components within lid housing portion 14 under display 16 toprovide a detachable tablet.

After assembly, portable information handling system 10 interfaces WNIC30 with antenna 40 through a cable 42, such as a coaxial cable thatprovides wireless signal communication. Main housing portion 12 and lidhousing portion 14 rotate relative to each other around hinge assembly36. For example, hinge assembly 36 includes synchronized hinges 38 thattranslate rotation motion between main housing portion 12 and lidhousing portion 14 with gears or other synchronization mechanisms. As aresult, the relative position of antenna 40 to the main and lid housingportions relates to the rotational orientation of hinge assembly 36.WNIC 30 selects one of plural antenna 40 (or plural sets of antenna asset forth below) based upon the location of the antenna relative to themain and lid housing portions. For example, a sensor associated withhinge assembly 36 provides relative rotational location to WNIC 30 toallow WNIC 30 to select an antenna 40 that is aligned to provideunobstructed communication to an external wireless device. Inalternative embodiments, other types of sensors may be used to determinehinge assembly 36 relative rotational position, such as Hall sensors andmagnets that determine proximity of upper and lower sides of main andlid housing portions relative to each other, or accelerometers thatdetermine relative orientation to gravity of main and lid housingportions.

Referring now to FIG. 2, a side perspective cutaway view depicts firstand second antennae 40 oriented relative to each other with main 12 andlid 14 housing portions in a closed position. Antenna 40 are disposed onopposing faces of hinge assembly 34 so that, in the closed position, oneantenna 40 is located at the outer periphery of information handlingsystem 10 while the opposing antenna 40 is in an internal position. Aslid housing portion 14 rotates relative to lid main portion 12 from theclosed to an open position, the relative orientation of hinge assembly34 changes, resulting in changes to the relative position of antenna 40.

Referring now to FIG. 3, a side perspective cutaway view depicts firstand second antennae 40 oriented relative to each other with main 12 andlid 14 housing portions in a tablet position. Rotation of hinge assembly34 during transition from the closed to the tablet configurations hasmoved the outer antenna 40 shown in the closed configuration to an innerposition in the tablet configuration, and has moved the inner antenna 40shown in the closed configuration to an outer periphery position in thetablet configuration. As depicted by FIGS. 4A and 4B, radiation patternsextending from a portable information handling system 10 are impacted bythe relative location of antenna 40 to the housing periphery. FIG. 4Adepicts a restricted radiation pattern that is transmitted from anantenna on an inner hinge face where housing structure interferes withradio frequency energy. In contrast, FIG. 4B depicts an optimizedradiation pattern 44 transmitted from an antenna located at an outerface of hinge assembly 34 with greater radio frequency efficiencyprovided by reduced housing structure interference.

In the example embodiment depicted by FIG. 3, each opposing face ofhinge assembly 36 has three evenly spaced antenna 40 that act as one setunder the control of a radio in WNIC 30. Other types of configurationsof antenna 40 may be used, such as a 2×2 configuration or an irregularspacing of antenna 40 across the face of hinge assembly 36. In variousembodiments, WNIC 30 uses one, two or all three of the antenna 40 on theouter periphery of hinge assembly 36 to communicate wireless signals.The antenna 40 on the inner face of hinge assembly 36 when not in usemay be altered to provide other functions. For example, inner faceantenna 40 may be de-tuned from the frequency used by WNIC 30 to avoidresonance with signals that transmit from antenna 40 on the outer face.Alternatively, one or more of inner face antenna 40 may be tuned toresonate at the transmitting frequency to absorb and retransmit RFenergy as a passive conductive element, such as for providingdirectional control of radiated energy. As another alternative, one ormore inactive antenna 40 on the inner face of hinge assembly 36 may begrounded to act as a ground for enhancing or shaping the RF energytransmitted from a selected antenna 40. In another alternativeembodiment, selection of antenna 40 is initially performed based uponthe orientation of hinge assembly 36 and then adjusted based uponantenna performance. For example, WNIC 30 tests radio performance todetermine which antenna 40 or set of antenna 40 provides the best returnsignal strength indication (RSSI) and uses the antenna 40 configurationwith the best RSSI. As an alternative to RSSI, WNIC 30 performs ananalysis based on bit rate error (BRE) and selects the antenna or set ofantenna that provides the best BRE. In one embodiment, the selection ofan antenna set to perform wireless communication is based upon thedistance of each antenna set from the ground plane of WNIC 30, withgreater distance to ground providing improved antenna efficiency.

Referring now to FIG. 5 depicts a side cutaway view depicts first andsecond antenna 40 coupled to opposing faces of a hinge 36. In oneexample embodiment, the antenna 40 located on the interior face of hinge36 has a distance of approximately 1.5 mm from the ground plane, whilethe antenna 40 on the outer face of hinge 36 has a distance ofapproximated 6.5 mm to the ground plane. The greater distance between anantenna 40 and a ground plane tends to provide better antennaefficiency. In addition, antenna 40 on the outer face of hinge 30 hasless obstruction caused by the housing surface. Although the exampleembodiment depicts first and second set of antenna 40 on opposing faces,in an alternative embodiment, additional antenna 40 may he included onother faces of hinge 36 and may include non-parallel andnon-perpendicular orientations that provide greater variations isantenna performance for intermediate rotational orientations, such as 90degrees of orientation in a clamshell configuration or 270 degrees oforientation in a tablet stand orientation.

Referring now to FIG. 6, a flow diagram depicts a process for selectingan antenna 40 based upon housing orientation. The process starts at step46 in an idle state awaiting a change in housing configuration. At step48, a determination is made if a change housing orientation is detectedand, if not, the process returns to step 46. If a change in housingorientation is detected, the process continues to step 50 to determineif the change is to a closed mode or to an open mode. If the housingconfiguration is changed to an open configuration, the process continuesto step 54 to confirm that the lid and main housing portions haverotated greater than 180 degrees, such as to a tablet configuration. Ifthe configuration has opened to a tablet mode or greater than 180degrees of rotation, the process continues to step 56 to select theantenna array located at the outer face of the hinge assembly at therelative housing rotation, then the process returns to step 46 tocontinue monitoring for changes in housing configuration. If at step 50,the relative housing configuration remains less than 180 degrees ofrotation, the process continues to step 52 to select the antenna setassociated with the outer hinge face at less than 180 degrees ofrotation, and then the process returns to step 46.

Referring now to FIG. 7, a flow diagram depicts a process for selectingan antenna based upon return signal strength and/or bit rate error.Although housing rotation orientation provides selection of an antennaset that likely has the best efficiency, in some instances other factorsmay impact actual antenna performance. The process starts at step 58 inan idle state monitoring RSSI (andior alternatively BER). At step 60, adetermination is made of whether RSSI (and/or BRE) has reached athreshold level. If not, the process returns to step 58. If a thresholdis reached that indicates a drop in antenna performance, the processcontinues to step 62 to select the other antenna array, even if therelative rotational position of the other antenna array is associatedwith an expected worse antenna performance. At step 64, the RSSI (andlorBRE) of the newly selected antenna is compared with the RSSI (and/orBRE) of the previously selected antenna. If the newly selected antennaprovides improved antenna efficiency, the process returns to step 58with the newly selected antenna enabled to provide wirelesscommunication. If the newly selected antenna does not provide betterperformance, the process continues to step 68 to select the previousantenna and to step 58 to continue wireless communication with theoriginal antenna. In alternative embodiments, similar comparison ofantenna performance may be done based upon implementation of anon-selected antenna in a detuned state, a tuned state or a groundstate.

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas defined by the appended claims.

What is claimed is:
 1. A portable information handling systemcomprising: a housing having main and lid portions; a processor disposedin the main housing portion and operable to execute instructions toprocess information; a memory disposed in the main housing portion andinterfaced with the processor, the memory operable to store theinformation; a radio disposed in the main housing portion and interfacedwith the processor, the radio operable to communicate wirelessinformation; a display disposed in the lid housing portion andinterfaced with the processor and memory, the display operable topresent the information as visual images; a hinge assembly rotationallycoupling the main and lid portions to each other, the hinge assemblyproviding substantially 360 degrees of rotation of the main and lidportions relative to each other; a first antenna disposed on a firstface of the hinge assembly, the first antenna interfaced with the radio;and a second antenna disposed on a second face of the hinge assembly,the second antenna disposed on a second face of the hinge assemblyopposite the first face; wherein the radio selects one of the first orsecond antenna to communicate wireless signals based upon one or morepredetermined factors.
 2. The portable information handling system ofclaim 1 wherein the one or more predetermined factors comprise arotational position of the main and lid housing portions relative toeach other.
 3. The portable information handling system of claim 2wherein the one or more predetermined factors further comprise an RSSIdetected at each antenna.
 4. The portable information handling system ofclaim 1 wherein the one or more predetermined factors comprise arelative position of the first and second antenna to a ground plane. 5.The portable information handling system of claim a wherein the one ormore predetermined factors comprise a bit rate error associated witheach antenna.
 6. The portable information handling system of claim 1wherein the unselected antenna is interfaced with ground.
 7. Theportable information handling system of claim a wherein the unselectedantenna is interfaced with a detuning circuit.
 8. The portableinformation handling system of claim 7 wherein the detuning circuitadapts the unselected antenna to re-radiate wireless signals form theselected antenna in a predetermined manner.
 9. A method forcommunicating wireless signals at a portable information handlingsystem, the method comprising: rotationally coupling main and lidhousing portions to each other with a hinge having first and secondopposing faces; disposing first and second antenna sets on the hingefirst and second opposing faces; determining the relative rotationalpositions of the lid and main housing portions to each other; and inresponse to the determining, selecting one of the first or secondantenna sets to communicate wireless signals.
 10. The method of claim 9further comprising: detecting hit rate error associated with theselected and unselected antenna. sets; and selecting the unselectedantenna set if the unselected antenna set has a lower bit rate error.11. The method of claim 10 further comprising: detecting a return signalstrength indicator associated with the selected and unselected antennasets; and selecting the unselected antenna set if the unselected antennaset has a greater return signal strength indicator.
 12. The method ofclaim 11 wherein the determining further comprises selecting the antennaset having a furthest distance to a ground plane of the informationhandling system.
 13. The method of claim 9 wherein the first antenna setcomprises three antenna disposed at spaced locations along the firsthinge face.
 14. The method of claim 9 further comprising detuning theunselected antenna set.
 15. A portable information handling systemantenna comprising: a hinge having first and second opposing facesconfigured to couple at one end to a main housing portion and at asecond end to a. lid housing portion; a first antenna set of pluralantenna disposed on the first hinge face; a second antenna set of pluralantenna disposed on the second hinge face; and a radio interfaced withthe first and second antenna sets, the radio operable to select one ofthe first or second antenna sets to communicate wireless signals basedon one or more predetermined conditions including at least the relativerotational position of the hinge.
 16. The portable information handlingsystem antenna of claim 15 wherein the predetermined conditions furthercomprise a comparison of bit rate error associated with the first andsecond antenna sets.
 17. The portable information handling systemantenna of claim 15 wherein the predetermined conditions comprise acomparison of return signal strength associated with the first andsecond antenna sets.
 18. The portable information handling systemantenna of claim 15 wherein the predetermined conditions comprise adistance of each antenna set from a ground plane of the main housingportion.
 19. The portable information handling system antenna of claim15 wherein the radio is further operable to detune the unselectedantenna set.
 20. The portable information handling system antenna ofclaim 15 wherein the radio is further operable to ground the unselectedantenna set.